Abstract
Diagnostic labels such as Chronic Fatigue Syndrome (CFS), Myalgic Encephalomyelitis (ME) and Systemic Exertion Intolerance Disease (SEID) represent different approaches to the enigmatic phenomenon of long-lasting unexplained fatigue.
More than 20 case definitions/diagnostic criteria for CFS/ME/SEID exist. All are based on subjective symptom reports, and the details of symptom requirement vary considerably. No one has been thoroughly validated.
The present thesis shows that adolescent CFS patients fulfilling the Canadian Consensus Criteria (CCC) or SEID-criteria do not differ from adolescent CFS patients diagnosed according to broad diagnostic criteria regarding neuroendocrine, cardiovascular, inflammatory, infectious or cognitive variables.
Furthermore, there appears to be no distinct subgroups within the overarching CFS label, but rather a continuum of subjective symptom experiences and pathophysiological aberrations.
These findings question the descriptive, predictive and construction validity of the CCC and SEID-criteria, and more fundamentally question the rationale of sub-classifying chronically fatigued patients based on clinical symptoms.
Rather, the results seem to suggest that all patients with an unexplained chronic fatigue may be seen as one entity in a qualitative sense, albeit with individual, quantitative differences regarding symptom severity and functional impairments.
Source: Tarjei Tørre Asprusten. Diagnosis of Chronic Fatigue Syndrome in Adolescents. https://www.duo.uio.no/bitstream/handle/10852/92148/PhD-Asprusten-2022.pdf?sequence=1 (Full PhD thesis)